Function handle_transform

src/api/InkAPITest.cc:7717–7825

static int64_t          append_buffer_length;

static void
handle_transform(TSCont contp)
{
  TSVConn output_conn;
  TSVIO   write_vio;
  int64_t towrite;
  int64_t avail;

  /* Get the output connection where we'll write data to. */
  output_conn = TSTransformOutputVConnGet(contp);

  /* Get the write VIO for the write operation that was performed on
     ourself. This VIO contains the buffer that we are to read from
     as well as the continuation we are to call when the buffer is
     empty. */
  write_vio = TSVConnWriteVIOGet(contp);

  /* Get our data structure for this operation. The private data
     structure contains the output VIO and output buffer.
  */
  auto *data = static_cast<AppendTransformTestData *>(TSContDataGet(contp));
  if (!data->output_buffer) {
    towrite = TSVIONBytesGet(write_vio);
    if (towrite != INT64_MAX) {
      towrite += append_buffer_length;
    }
    data->output_buffer = TSIOBufferCreate();
    data->output_reader = TSIOBufferReaderAlloc(data->output_buffer);
    data->output_vio    = TSVConnWrite(output_conn, contp, data->output_reader, towrite);
  }
  ink_assert(data->output_vio);

  /* We also check to see if the write VIO's buffer is non-NULL. A
     NULL buffer indicates that the write operation has been
     shutdown and that the continuation does not want us to send any
     more WRITE_READY or WRITE_COMPLETE events. For this simplistic
     transformation that means we're done. In a more complex
     transformation we might have to finish writing the transformed
     data to our output connection. */
  if (!TSVIOBufferGet(write_vio)) {
    if (data->append_needed) {
      data->append_needed = 0;
      TSIOBufferCopy(TSVIOBufferGet(data->output_vio), append_buffer_reader, append_buffer_length, 0);
    }

    TSVIONBytesSet(data->output_vio, TSVIONDoneGet(write_vio) + append_buffer_length);
    TSVIOReenable(data->output_vio);
    return;
  }

  /* Determine how much data we have left to read. For this append
     transform plugin this is also the amount of data we have left
     to write to the output connection. */
  towrite = TSVIONTodoGet(write_vio);
  if (towrite > 0) {
    /* The amount of data left to read needs to be truncated by
       the amount of data actually in the read buffer. */
    avail = TSIOBufferReaderAvail(TSVIOReaderGet(write_vio));